Various processes have been proposed for the removal of nicotine from tobacco. Most of these processes, however, are not sufficiently selective for nicotine and remove other ingredients from the tobacco. Removal of these other ingredients adversely affects the desirable flavor and aroma properties of the tobacco. Other processes generally have been found to be limited in their scope and effectiveness and are often complex and expensive to carry out.
Nicotine has been extracted from tobacco using organic solvents with and without neutralization of the nicotine salt. Representative of such processes are those disclosed in U.S. Pat. Nos. 678,362 (Froehling), 1,196,184 (Villiers-Stuart), 2,048,624 (Roselius), 2,128,043 (Garner), 2,227,863 (Rhodes) and 3,096,773 (Neukomm et al.). Nicotine has also been extracted from tobacco with aqueous solutions with and without neutralization of the nicotine salt. Representative of such processes are those disclosed in U.S. Pat. Nos. 2,822,306 (Thienemann et al.), 2,582,075 (Severi) and 3,874,392 (De Brunn et al.). Nicotine has been separated from solutions of tobacco extracts and the nicotine depleted solvent returned to the tobacco. Representative of such processes are those disclosed in U.S. Pat. Nos. 283,622 (Liebreich et al.), 802,487 (Wimmer), 2,805,667 (von Bethmann), 3,046,997 (Hind), and 3,139,435 (Staley et al.). Nicotine has also been separated from solutions of tobacco extracts and the depleted solvent saturated with the other components recycled to the extraction vessel. Representative of such processes are those disclosed in U.S. Pat. Nos. 1,294,310 (Sayre et al.), 1,577,768 (Smith), 1,813,833 (Andrews), 3,396,735 (von Bethmann) and 3,612,066 (Jones).
Nicotine has been transferred from tobacco to a substrate without the use of a solvent by contacting the tobacco intimately with a substrate which has been treated with an acid as disclosed in U.S. Pat. No. 4,215,706 (Larson). This process may be carried out with or without heat.
U.S. Pat. No. 4,153,063 (Roselius) discloses a process for removing nicotine from tobacco in which tobacco is contacted with an extraction solvent in a supercritical state. In a single step extraction process, moist tobacco is extracted with a solvent in a supercritical state. Thereafter the solvent is evaporated. Because aroma components are also removed along with nicotine in this single step extraction process, a multi-step process has been suggested. In the first step, dry tobacco is extracted with a solvent in the supercritical state to remove the aroma components. In the second step, the tobacco is moistened and again extracted with a solvent in the supercritical state to remove nicotine which is separated by either evaporating the solvent, contacting the solvent in a separate vessel with an acid, or adsorbing the nicotine on an active carbon column. In the third step, the stored aroma components from the first step are redissolved in a supercritical solvent and returned to the tobacco. This multi-step extraction process is expensive and time consuming. In addition, the prolonged handling of the aroma components may adversely affect their properties.